Ali Akbar Majidi-Jirandehi - Department of Mechanical Engineering, Payame Noor University (PNU), P.O. Box. ۱۹۳۹۵-۳۶۹۷, Tehran, Iran
Moslem Mohammadi Soleymani - Department of Mechanical Engineering, Payame Noor University (PNU), P.O. Box. ۱۹۳۹۵-۳۶۹۷, Tehran, Iran
Hossein Dehghani - Department of Mechanical Engineering, Shahid Bahonar University, Kerman, Iran

Today, many car manufacturers can achieve emission standards through catalytic converters. The goals of this research was in tow sections. Initially, the amount of pollutants was measured to determine the role of the catalytic converters in the reduction of pollutants for ۳ types of vehicles and in ۵۰ cases, in the two stages before and after the catalytic converter. Then, to achieve the useful life of the catalytic converter, out of ۷۵۰ test vehicle emissions were tested. Data analysis was done by SPSS software, which shows that catalytic converters can reduce up to ۸۰% of exhaust emissions. This is independent of the type of vehicle. The useful life of the catalytic converters is up to ۳۶ months, so they should be replaced at least every three years. Also, the pollutant standards of the technical examination centers are reviewed. For this purpose, the pollutants have been measured in ۲۲۰۰ vehicles. Due to the huge difference in technology, cars are divided into two main categories of carburetor and injector and are analyzed statistically. Eventually, for each group of these vehicles, the values of HC, CO and O۲ are obtained.

Catalytic Converters, Pollutants, Pollution standard, Technical Inspection